Grey squirrels are an invasive species in the U.K., where they threaten the survival of the beloved native red squirrels. Some British restaurants have put grey squirrel dishes on their menus, and one company even sells grey squirrel pate--accented with hazelnuts and Frangelico--and donates the proceeds to a red squirrel conservation group.

The meat is low-fat and sustainable, but it's not exactly popular. More than half the grey squirrel population is infected with the squirrelpox virus, says Richard Wales, the project officer at the conservation group Red Squirrels in South Scotland. The virus is harmless to humans, he says, but "it hardly makes the eating of them an attractive proposition for the average U.K. family."